Gas entrained lump-breaking and drying equipment



R. L. MORRISON 2,808,213

GAS ENTRAINED Lum-BREAKING AND DRYING EQUIPMENT Filed Jan. 13, 1954INVENTOR.

Robe/'f L. Morrison BY @4% jfv@ ATTORNEY \m R Q I m |||V| \V Oct. l,1957 United States Patent 2,808,213 Patented` Oct. 1, 1957 hce 2,808,213oA'sfnNrnAnvnD nUMP-BREAKnsG' ANDV DRYING'EQUIP-MENT RobertLanrance-VMorrison, Blairmore,Albert, Canada,

assignor to.. West Canadian. Collieries, Limited, Blairmore, Alberta,Canada, a corporation of Canada Application January 1s, 1954, serial No.403,829:

e claims.. (c1. 2211-40) This invention relatestoapparatus-for the rapidand continu-ous drying of finely divided materials lby the direct heatexchange with hot'gases at high velocities. The apparatus relates moreparticularly to improvements in uidized or gas entrained dryingequipment.

Apparatus for-drying finely divided' solids in a-liigh velocity streamof hot gases is generally known. Such apparatus consists ofar combustionfurnace for generating hot gases, ai drying chamber for entrainingfinely divided `material inan uprising stre-am` of the hot gas, and a.separator forseparating dried material from the spent gases issuing outof the drying chamber. In such apparatus the -hot gases from` thecombustion furnace are passed through a rather narrow passage or neckupwardly into a drying chamber. The wet, finely divided material isintroduced into the drying gases inthe neck, so as t-o suspend thematerial in the rising hot gases. The neck expands and connects with thebodyvof the drying-chamber above the rpoint of solidsintroduction. Thesus# pended solids are maintained in a iluid-ized or-gas entrained statein the enlarged portion ofethe dryingfchamber until the particlessbecomesubstantially dry, when they are substantiallylighter in weight, atwhich point the dried solid-material is carried upandaoutof the dryingchamber. A separator then recovers the dried product from the spentgases.

4The presentinvention provides an improvement over the known driers ofthe prior art. In the driers as known, there is a grading or otherpressure or Velocity equalization constriction means across the hot gasinlet into the drying chamber. These constrictionstend to .aid theentrainment ofthe solids in the gas. With certain operations, however,very wet coal is encountered,especially wherelow rank coal has beenextensively washedto remove rock-and ash impurities. The coal dischargedfrom such a washing operation is of the character of a sludge, whichcannot be dewatered within practical limits by mechanical means. The4sludge packs or'lurnpsv into large particles which .are not readilyentrained and dried in the drying chamber, and drop through theentraining constrictions, out of the drying cham-ber. Feed devices havebeen suggested for -breaking up the lumps, however, these have not beenpractical. It is an .object of the .present invention to provide animproved device for the fluidized or gas entrained heat transfer ordrying of finely divided wet solids.

llt is another object of the invention to provide a simple and eflicientfeed mechanism for wet coals and the like for hot gas driers.

yIt is still another object of the present invention to provide animproved method of the entraining of finely divided wet solids in astream of hot gases.

These and other objects of the invention Will be readily apparent byreferring to the following description and appended drawings in which:

Fig. l is a sectional View of the device according to the invention,including a partial view of auxiliary equipment used with the device.

`In the-device selected for illustration, a combustion furnace 10, onlyjpartly shown in Fig. 1 as it does not form a part of the invention,provides a stream offhot gases for drying solid material. The hot gasessweep down they furnace 10 around a bend 1-1 into a neck12 of a dryingchamber 17. Swirl .producing/vanes 14 at the lower end of an entrainingportion 15, violently swirl the hot gases, and baffles 16 directly abovethe vanes tend topstraighten thewhirling-gases-into straight line flowupthe drying neck 15. The swirl vanes and .baffles aid in providing' auniform pressure or velocity gradient across the entraining neck 15, formore eicient material spread and,` therefore, more etiicient drying. Wetcoal is fed' by the feed'means 28 into the entraining chamber 15. Thewet solidvis dropped generally toward the swirl andbaiiie means, and ispicked up in the hot gases in the swirl means and-isentrained in thegases rising up through the chamber 15;

A by-pass 18l passes around the swirl producing means 14-and the baiiies16 and exhausts immediately adjacent the feedmeans .outlet 30 in'chamber15. The inlet 20 to the by-pass V18 isared-Hto act as a scoop for thehot gases throughthe by-pass. The resistance to flow through the by-pass131s :less than through the swirl producing means, and so apart of thegas will pass through the =bypass means. The bydpass is smallenough,rhowever, that the majority ofthe gas .passes through the swirlvanes for entraining solids fed into the drier. rilhe 'outlet 22 of theibyfpasslSis'ilattened 'to substantially increase the velocity/*oftheby-passed gas issuing from the outlet 22.` Thefeed means 28' consists ofa screw conveyor which has-an'outletl 30 `along the Wall of the drier.The wet material ybeing exhausted from the feed outlet 30 falls directlyintothe jet stream issuing from outlet 22, and--is -picked up. inv thejet stream'and carried across the drying column :and -forceafbly throwninto `the wall ataibout point 24.- rIlhe lumps which hit the `wa'll areeffectively broken up andas they fall` from their'conta-ct with thewallthey are -picked'inthe gas stream andare .entrained for drying.

Aspiral conveyor 32is provided directly beneathithc drying chamberyinlet 15 to remove ash brought over by the hot ngases from thecombustion furnace 10 :and any largelumps of the-material which may dropthrough the lswirl producing means 14.

In general, the `by-pass 18-provides a smooth, circular conduit fortpassing a portion of the hot combustion gases aroundthe swirl producingmeans into the entraining chamber at 15. Theiby-pass is attened andsomewhat reducedY in area at the-outlet 22 soas'to form a gas jet streamof highv velocity directly nextto'the outlet 30 of the feed means 28.The flattened end ZZeXtends sub'- stantially across the diameterof theoutlet 30,` soy that any coal dropping from the feed means will .bepicked up in the jet stream and will be forced across the drying chamberonto the wall 24. This jet stream insures all material issuing from thefeed means will ibe broken into small particles for entrainment in therising stream of hot gases.

vOthers may readily adapt the invention to various conditions andvarious modes of operation without departing from the spirit and thescope of the invention. It will .be apparent to those skilled in the artthat the invention rnay .be modified without departing from theinventive concept.

II claim:

1. In apparatus for drying subdivided materials in a gas entrainedstate, an upright drying column, means for introducing heated gases intothe lower en-d of said column, means for introducing material insubdivided :condition into ysaid column above its ybottom adjacent theside wall thereof, la series of vanes in said column intermediate saidmeans for introducing said gases and said material for entraining saidmaterial in said gas, and a llay-pass duct means interconnected withsaid column for conducting a portion of said heated gases around saidvanes, said duct means having a iiared inlet forming a scoopinterconnected with and adjacent the lower end of said column and aconstricted outlet adjacent the material inlet to said column, saidoutlet being arranged to provide a high velocity stream of gas directedtransversely across said column whereby material may be entrained insaid gas stream therefrom and be forced against the opposite wall tobreak up lumps of particles to be suspended in said gases.

2. yIn apparatus for drying subdivided materials in a gas entrainedstate, an upright drying column, means for introducing heated gases intothe lower end of said column, means for introducing material insubdivided condition into said column above its bottom adjacent the sidewall thereof, swirl producing means in said column intermediate saidmeans for introducing said gases and said material, and by-pass ductmeans interconnected with said column for conducting a portion of saidheated gases around said swirl producing means, said duct means having aared inlet form-ing a scoop interconnected with the lower end of saidcolumn and a restricted outlet interconnected with said Icolumn ibelowand adjacent the material inlet to said column, said outlet beingarranged to provide a high velocity stream of gases directedtransversely across said column whereby material may be ,forced againstthe opposite wall to break up lumps of particles to be suspended in saidgases.

3. `In apparatus for drying subdivided materials in a lgas entrainedstate, an upright drying column, means for introducing heated gases intothe lower end of said column, screw conveyor means for introducingmaterial in subdivided condition into said column above its bottom:adjacent the side wall thereof, velocity equalizing means in saidcolumn intermediate said gas introducing means and said conveyor meansfor entraining material uniformly across said column, and a by-pass ductfor conducting a portion of said heated gases around said velocityequalizing means, said duct having a ared inlet yforming a scoopcommunicating with the lower end of said .column and a restricted outletcommunicating with said column adjacent the material inlet, said outletbeing arranged to provide a high velocity stream of gases directedtransversely across said column whereby material from said screwconveyor means may be entrained and forced against the opposite Wall tobreak up lumps of particles to be suspended in said gases.

4. lIn apparatus for drying subdivided materials in a gas entrainedstate, an upright drying column, means for introducing heated gases intothe lower end of said column, means for introducing material insubdivided condition into said column above its bottom, swirlimpartcentrifugal movement to a portion of the entering gas to entrainsaid solids, and lay-pass duct means interconnesting the lower end ofsaid column with a point thereabove for conducting 4the remainder of theentering gas -around said swirl means, said duct means having an outletcommunicating with said column below and in proximity to the materialintroduction means arranged to entrain material in a stream from saidduct and direct it onto Ithe column wall for breaking up lumps ofmaterial for suspending the same in said gases.

5. In apparatus for drying subdivided materials in a gas entrainedstate, an upright drying column, means for Y introducing heated -gasesinto the lower end of said column, means for introducing material insubdivided condition into said column above its bottom, swirl impartingmeans and baile means in the column intermediate said means forintroducing said gases and material to entrain solids uniormly acrosssaid chamber, and by-pass duct means interconnecting the lower end ofsaid column with a point above said swirl imparting and baille means forconducting the remainder of the entering gas around said swirl means,said duct means having an outlet located below and in proximity to thematerial introduction means arranged for breaking up lumps of materialand for suspending the same in said gases.

6. In apparatus for drying subdivided materials in a gas entrainedstate, an upright drying column, means for introducing heated gases intothe lower end of said column, screw conveyor means for introducingmaterial into subdivided condition into said column above its bottom,said conveyor means exhausting adjacent the wall of said column, swirlimparting means in the column intermediate said points of introductionconstructed and arranged yto disperse the divided material across thecolumn, and by-pass duct means interconnecting the lower end of saidcolumn and an upper portion thereof for conducting a portion of saidheated gases extending around said swirl means, the outlet of saidby-pass duct means being A restricted for providing a high velocitystream of gas ing means in the column intermediate said means forIintroducing gases and material and arranged to impart below saidconveyor whereby material from the conveyor means is carried across thechamber and impacted into the opposite wall to break up lumps ofmaterial to be suspended.

References Cited in the tile of this patent UNITED STATES PATENTS301,513 Newton July 8, 1884 2,021,171 Buck Nov. 19, 1935 2,272,564Kuever Feb. l0, 1942 2,339,932 Kuhl Ian. 25, 1944 2,587,020 Wicker et alFeb. 26, 1952 2,607,537l Shaw Aug. 19, 1952 FOREIGN PATENTS 488,714Germany Jan. 7, 1930

